"New Labour didn't see with sufficient clarity the downsides of globalisation. They knew it meant cheap consumer goods. But they didn't recognise that too often it meant cheap labour too.

“It's a false choice to say we must either champion Labour's record in government or denounce it. The truth is we should defend our achievements and learn from our mistakes. To anyone outside Westminster, that's common sense.”

Mr Jarvis, a former member of the Parachute regiment who served in Iraq and Afghanistan, entered Parliament in a by-election in 2011.

Bookmakers William Hill have now shortened his odds from 10/1 to 4/1 second favourite to replace Mr Corbyn as leader.

The speech on Thursday at the thinktank Demos will be seen as Jarvis taking on criticism that he is too far to the right and positioning himself on the soft left of the party.

Mr Jarvis made a plea for the union vote, saying they can protect one third of British jobs from being done by computers and robots.

He said: “At a time when many workers feel weak those who stand up for them must be strong – this does not mean a return to the 1970s.

“Today the nature of work and the type of jobs available is changing. The Labour market which has changed beyond recognition in my lifetime will change again as a result of automation.

“Jobs like check out assistants, cleaners and truck drivers may no longer exist.

“So that is where I believe the trade union movement can play a pivotal role because since their foundation trade unions have both protected and educated workers.”

Mr Jarvis called on Labour to put tackling inequality at the heart of its policy agenda, criticising previous Labour Governments for not doing enough.

“Put simply, Labour needs to be tough on inequality, tough on the causes of inequality,he said, echoing former Labour leader Tony Blair’s famous promise to be “tough on crime and tough on the causes of crime”.

Dan Jarvis in his previous job Photo: PA

Asked about his leadership ambitions, Mr Jarvis said his only focus was on the May elections to the Scottish Parliament and English local councils, and the EU referendum.

He said he had no regrets about deciding not to stand for the Labour leadership after last May’s general election defeat.

He said: “We’ve lost two general elections fairly badly, I don’t want to lose a third election. I'm very comfortable with the decision I took in May last year.”

Mr Jarvis also made clear that he would defy any attempts by hard left group Momentum to pressure him to move to the left insisting that he was not a “delegate” of his local party

He said: “Labour MPs need to listen to local party members but of course they also need to listen to their constituents as well.

“As a Labour MP I am not a delegate of my own local party I have been elected to Parliament by my constituents to stand up for them.”

The news came as Stephen Kinnock, the Labour MP and son of the former leader Neil Kinnock, said that Labour needs “a big jump forward” in the English council elections for Mr Corbyn to be sure of staying on as leader.

He told the Huffington Post that May's local elections would go a long way towards showing whether Mr Corbyn was a potential prime minister.

He said: "The big question is when people look at him do they see somebody who could be the next prime minister of the United Kingdom and I think we will know a large part of the answer to that question following the elections on May 5 and also how the Labour party carries itself now through to the 23rd June and the referendum.

"Jeremy, as any leader, gets judged on performance, gets judged on results, so until we see what those results are opinion polls – as we saw with the 2015 election – they are not worth the paper they’re written on."